I had a new lobster boat built and took delivery of the vessel in December 2009. The Garmin system has not functioned correctly since day one. The boat builder and Garmin have been to my boat on several occasions but have failed to fix the problems. They have now fitted a larger autopilot pump but have connected it to the original hydraulic pipes. These have a working pressure of 625 psi and the new pump has a working pressure of 900 psi. Yes your thoughts are correct it blew the pipe out of the pump while I was at sea. You can view the problems on youtube by searching for cheetah catamaran. Or you can use the link below. I strongly advise everyone not to buy the Garmin Marine Autopilot.
http://www.youtube.com/watch?v=ZQJgf2wkE9s